Graphic artifact around cursor and on screen
I am experiencing the following problems with my 24 inch Mid 2007 iMac since upgrading to Mavericks (currently OS X 10.9.5 (13F1112))
1) I get strange graphical artefact moving around onscreen along with my cursor (A1). This artefact appears on both my iMac screen and my second screen.
2) They do not show up if I create a screen capture.
3) I get similar screen artefacts in the area known as the menu area at the top my main screen (A2). With A2, one appears over the Apple Logo at the top left and repeats at regular interval along the top of my screen. If the Menu Bar is visible they are light blue (cyan) in colour or red when in full screen mode.
4) They flicker on and off when the screen saver is operating.
5) A1 and A2 appear when the account chooser screen is displayed and it doesn’t matter what account I use.
6) A1 also appears on my second display but no A2. Only A2 appears on my iMac’s display.
7) A2 appear in the grey boot up screen, even when booting into Safe Mode.
8) It seems to be gradually getting worse. Today they also appear half way down and across the screen.
9) As neither appears if I do a screen capture I attach a drawing as illustration.
Although it doesn't show the artifacts that follow my cursor around, the attached movie shows the ones that are on the screen and in the menu bar. I tried to highlight them by drawing a rectangle over or near them.
The following has neither identified nor solved the problem -
i) Re-installing Mavericks
ii) Booting from Rescue Drive
iii) Booting from TechTool “eDrive”. TechTool Pro 8 screen memory tester - Passed. Made them flicker though, same as with screen saver.
iMac, OS X Mavericks (10.9.5), iMac 24 Mid 2007;
